Electric socket ratchet wrench and method of using the same

Abstract

An electric socket ratchet wrench includes a body, a driving device rotatably mounted in the body, a pawl device coupled with the driving device, a power device providing a torque, a transmission device between the driving device and the power device, and a clutch device. The driving device includes a driving member having a non-circular hole for coupling with a fastener. The driving member includes an annular toothed portion coupled with the pawl device and an end toothed portion coupled with the transmission device. When a resistance smaller than the torque is encountered while the driving member is driving the fastener, the driving member continuously drives the fastener. When a large resistance larger than the torque is encountered at a position, the body is manually rotatable by a torque larger than the large resistance to forcibly drive the fastener through the position via the driving member.

The invention claimed is: 
     
       1. An electric socket ratchet wrench comprising:
 a body including a first end having a first abutment face and a second end opposite to the first end; 
 a driving device including a driving member rotatably mounted in the first end of the body, with the driving member including a large diameter section connected to a middle diameter section, with the large diameter section abutting the first abutment face of the body, with the driving member further including an annular small diameter section connected to the middle diameter section, with the middle diameter section having two ends respectively connected to the large diameter section and the annular small diameter section, with a first outer diameter of the large diameter section being larger than a second outer diameter of the middle diameter section, with the second outer diameter of the middle diameter section being larger than a third outer diameter of the annular small diameter section, with the driving member further including a non-circular hole extending through the driving member, with the non-circular hole adapted to engage with a fastener, with the driving member further including an annular toothed portion and an end toothed portion, with the annular toothed portion and the end toothed portion disposed on the middle diameter section, and with the annular toothed portion integrally formed on an outer periphery of the second outer periphery diameter of the middle diameter section in a circumferential direction of the middle diameter section, and wherein the end toothed portion is integrally formed on an end face of the middle diameter section, the end face being along a junction between the middle diameter section and the annular small diameter section; 
 a pawl device mounted in the first end of the body and coupled with the annular toothed portion of the driving member; 
 a power device mounted in the second end of the body and configured to provide a torque; 
 a transmission device mounted between the driving device and the power device, with the transmission device rotatably mounted to the body and connected to the end toothed portion of the driving member, with the transmission device configured to transmit the torque from the power device to drive the driving member to rotate relative to the first end of the body; and 
 a clutch device mounted between the driving device and the power device, with the clutch device switchable between an engaged state and a disengaged state, 
 wherein when a resistance smaller than the torque outputted by the power device is encountered while the driving member is driving the fastener, the clutch device is in the state, and the power device drives the transmission device to actuate the driving member to rotate relative to the first end of the body, thereby continuously driving the fastener to rotate, and 
 wherein when a large resistance larger than the torque outputted by the power device is encountered at a position while the driving member is driving the fastener, the clutch device is in the disengaged state, the transmission device does not transmit the torque of the power device to the driving member, the body is manually rotatable by a manual torque larger than the large resistance to overcome the large resistance and to forcibly drive the fastener through the position via the driving member, and the clutch device returns to the engaged state after the fastener passes through the position. 
 
     
     
       2. The electric socket ratchet wrench as claimed in  claim 1 , with the body including a driving hole defined in the first end of the body and extending through the first abutment face, with the driving member rotatably mounted in the driving hole, with the end toothed portion formed in the circumferential direction of the middle diameter section, with the driving member further including an abutment face at the large diameter section, with the abutment face of the driving member abutting the first abutment face of the body. 
     
     
       3. The electric socket ratchet wrench as claimed in  claim 2 , with the driving member rotatable about a driving axis, with the driving hole including a top end and a bottom end opposite to the top end along the driving axis, with the top end located adjacent to the first abutment face of the body, with the driving hole including an inner periphery having an inverted conical portion connected to the first abutment face and a rectilinear portion connected to the inverted conical portion, with the inverted conical portion having decreasing diameters from the top end toward the rectilinear portion, and with an angle between the inverted conical portion and the rectilinear portion being in a range between 170 degrees and 180 degrees. 
     
     
       4. The electric socket ratchet wrench as claimed in  claim 3 , with the first end of the body further including a second abutment face opposite to the first abutment face, with the driving hole further including a supporting portion protruding toward the driving axis from the rectilinear portion in a radial direction perpendicular to the driving axis and located adjacent to the bottom end, with the second abutment face formed on an end face of the supporting portion, with the driving member further including an engaging groove in a third outer periphery of the annular small diameter section, with the second outer periphery diameter being larger than the third outer periphery, with the driving device further including an engaging unit mounted in the engaging groove, and with the engaging unit abutting the second abutment face of the body. 
     
     
       5. The electric socket ratchet wrench as claimed in  claim 4 , with the engaging unit including a retaining member mounted in the engaging groove and a washer pressed by the retaining member, with the washer mounted between the retaining member and the supporting portion, with the retaining member including at least two loops to provide an elastic force pressing against the washer, with the washer pressing against the second abutment face of the body to prevent the driving member from moving along the driving axis relative to the driving hole. 
     
     
       6. The electric socket ratchet wrench as claimed in  claim 4 , with the engaging unit including a retaining member mounted in the engaging groove, a washer pressed by the retaining member, and a ball unit pressed by the washer, with the ball unit of the engaging unit including a plurality of balls between the washer and the second abutment face of the body, with the ball unit of the engaging unit reducing friction between the washer and the second abutment face, with the retaining member including at least two loops to provide an elastic force pressing against the washer, with the washer pressing against the ball unit of the engaging unit, with the ball unit of the engaging unit pressing against the second abutment face of the body to prevent the driving member from moving along the driving axis relative to the driving hole. 
     
     
       7. The electric socket ratchet wrench as claimed in  claim 5 , with the body further including a compartment formed in the first end and intercommunicated with the driving hole, with the body further including a through-hole intercommunicated with the compartment, with the pawl including a switch pivotably mounted in the through-hole, a pawl slideably mounted in the compartment, and a pressing unit mounted between the switch and the pawl, with the pawl meshed with the annular toothed portion of the driving member, with the pressing unit including a pressing member and a spring, with the pressing member pressing against the pawl, with the spring mounted between the pressing member and the switch and providing an elastic force pressing against the pressing member, with the switch controlling a biasing position of the pressing unit to control an engagement relationship between the pawl and the annular toothed portion to achieve a direction switching function of the driving device. 
     
     
       8. The electric socket ratchet wrench as claimed in  claim 7 , with the body further including a transmission hole intercommunicated with the driving hole and a chamber defined in the second end of the body and intercommunicated with the transmission hole, with the power device mounted in the chamber and including a motor and a power source electrically connected to the motor, with the motor having a shaft adapted to be driven by electricity supplied by the power source, with the transmission device including a transmission shaft rotatably mounted in the transmission hole about a rotating axis and a gear, with the transmission shaft including a driving end and a transmission end opposite to the driving end, with the gear disposed on the driving end of the transmission shaft and meshed with the end toothed portion of the driving member, with the transmission shaft further including an annular groove in the driving end, with the transmission device further including a ball unit including a plurality of balls mounted in the annular groove and in contact with an inner periphery of the transmission hole, and with the ball unit of the transmission device reducing friction between the transmission shaft and the inner periphery of the transmission hole. 
     
     
       9. The electric socket ratchet wrench as claimed in  claim 8 , with the clutch device including a driver member and a driven member, with the driver member mounted on the shaft of the motor, with the driven member movably mounted on the transmission end of the transmission shaft and movable along the rotating axis, with the driver member having a first toothed portion, with the driven member having a second toothed portion, with each of the first toothed portion and the second toothed portion having a plurality of teeth, with the plurality of teeth of the second toothed portion movable along the rotating axis to disengageably engage with the plurality of teeth of the first toothed portion to thereby switch the clutch device between the engaged state and the disengaged state, wherein when the resistance smaller than the torque outputted by the motor is encountered while the driving member is driving the fastener, the driver member and the driven member of the clutch device are in the engaged state, and the first toothed portion of the driver member engages with the second toothed portion of the driven member, with the motor driving the driver member to actuate the driven member and the transmission shaft, and with the gear, actuating the driving member to rotate about the driving axis to thereby drive the fastener to rotate, and wherein when large resistance larger than 3 newton meters is encountered at a position while the driving member is driving the fastener, the driver member and the driven member of the clutch device are in the disengaged state, and the driven member moves relative to the transmission end of the transmission shaft along the rotating axis, with the second toothed portion of the driven member moves along the rotating axis, resulting in a semi-clutching phenomenon in which the second toothed portion of the driven member repeatedly engages with and disengages from the first toothed portion of the driver member, such that the transmission shaft and the gear do not transmit the torque of the motor to the driving member, the body is manually rotatable by a manual torque larger than the large resistance to overcome the large resistance and to forcibly drive the fastener through the position via the driving member, and the driver member and the driven member return to the engaged state after the fastener passes through the position. 
     
     
       10. The electric socket ratchet wrench as claimed in  claim 9 , with the driver member including a first receptacle extending along the rotating axis, with the first receptacle having an end wall, with the driven member including a second receptacle extending from an end through another end of the driven member along the rotating axis, with the clutch device further including an elastic unit and a ball, with the transmission end of the transmission shaft extending through the elastic unit and the second receptacle of the driven member and coupled with the first receptacle of the driver member, with the elastic unit providing an elastic returning force pressing against the driven member to set a preset torque value, with the ball reducing friction between the transmission end of the transmission shaft and the end wall of the first receptacle, wherein when the larger resistance encountered during driving of the fastener by the driving member is larger than the torque outputted by the motor or the preset torque value of the elastic unit, the driver member and the driven member of the clutch device are in the disengaged state, and the driver member moves along the rotating axis relative to the transmission end of the transmission shaft to press against the elastic unit, thereby repeatedly and elastically deforming the elastic unit. 
     
     
       11. A tool set comprising:
 a pass-through socket including a groove defined in an outer periphery of the pass-through socket; and an electric socket ratchet wrench including: 
 a body including a first end having a first abutment face and a second end opposite to the first end; 
 a driving device including a driving member rotatably mounted in the first end of the body, with the driving member including a large diameter section connected to a middle diameter section, with the large diameter section abutting the first abutment face of the body, with the driving member further including an annular small diameter section connected to the middle diameter section, with the middle diameter section having two ends respectively connected to the large diameter section and the annular small diameter section, with a first outer diameter of the large diameter section being larger than a second outer diameter of the middle diameter section, with the second outer diameter of the middle diameter section being larger than a third outer diameter of the annular small diameter section, with the driving member further including a non-circular hole extending through the driving member, with the non-circular hole adapted to engage with a fastener, with the non-circular hole including an inner periphery having a positioning groove, with a positioning member mounted in the positioning groove and engaged in the groove of the pass-through socket, with the driving member further including an annular toothed portion and an end toothed portion, with the annular toothed portion and the end toothed portion disposed on the middle diameter section, with the annular toothed portion integrally formed on an outer periphery of the middle diameter section in a circumferential direction of the middle diameter section and wherein the end toothed portion is integrally formed on an end face of the middle diameter section along a junction between the middle diameter section and the annular small diameter section; 
 a pawl device mounted in the first end of the body and coupled with the annular toothed portion of the driving member; 
 a power device mounted in the second end of the body and configured to provide a torque; 
 a transmission device mounted between the driving device and the power device, with the transmission device rotatably mounted to the body and connected to the end toothed portion of the driving member, with the transmission device configured to transmit the torque from the power device to drive the driving member to rotate relative to the first end of the body; and 
 a clutch device mounted between the driving device and the power device, with the clutch device switchable between an engaged state and a disengaged state, 
 wherein when a resistance smaller than the torque outputted by the power device is encountered while the driving member is driving the fastener, the clutch device is in the engaged state, and the power device drives the transmission device to actuate the driving member to rotate relative to the first end of the body, thereby continuously driving the fastener to rotate, and 
 wherein when a large resistance larger than the torque outputted by the power device is encountered at a position while the driving member is driving the fastener, the clutch device is in the disengaged state, the transmission device does not transmit the torque of the power device to the driving member, the body is manually rotatable by a manual torque larger than the large resistance to overcome the large resistance and to forcibly drive the fastener through the position via the driving member, and the clutch device returns to the engaged state after the fastener passes through the position. 
 
     
     
       12. The tool set as claimed in  claim 11 , with the positioning groove located at an intermediate portion of the inner periphery of the non-circular hole of the driving member, and with the positioning member formed by a metal wire and extending along the positioning groove.